Method for molding ophthalmic lenses

Abstract

The invention concerns a method for moulding a lens, between a first mould ( 2 ) and a second mould ( 6 ) which consists in: machining at least one of the moulds ( 2 ) into the shape of the lens to be obtained, before moulding. The invention enables to obtain finer lenses, while limiting the required amount of hardenable material for making the lens.

1. A method for molding a non-circular lens adapted to a wearer's prescription and to the shape of a frame chosen by the wearer, comprising the steps of:
 supplying a non-circular first mold substantially in the shape of the frame chosen by the wearer; 
 supplying a second circular mold; 
 molding and curing a setting material between the first mold and a second mold, a maximum size of the first mold between two points of its perimeter being less than a diameter of the second mold; 
 removing the cured material from the first and second molds to define the lens, and 
 securing the lens to the frame, wherein the periphery of the cured material is not trimmed by more than a few millimeters prior to securing the lens to the frame. 
 
   
   
     2. The method as claimed in  claim 1 , wherein the step of supplying a first mold comprises a step of trimming said mold. 
   
   
     3. The method as claimed in  claim 1 , wherein the curing step is a step of partial curing, and wherein the method further comprises a step of total curing of the lens. 
   
   
     4. The method as claimed in  claim 1 , wherein the step of molding and curing comprises a step of assembling the molds followed by a curing step. 
   
   
     5. The method as claimed in  claim 3 , wherein the partial curing step lasts less than 3 minutes. 
   
   
     6. The method as claimed in  claim 3 , wherein the total curing step lasts between 5 and 30 minutes. 
   
   
     7. The method as claimed in  claim 4 , wherein the step of assembling comprises using mold-positioning devices and wherein the method further comprises a step of removing the mold-positioning devices after the partial curing step and before the total curing step. 
   
   
     8. The method as claimed in  claim 3 , wherein the partial curing step comprises an irradiation of the setting material from only one side of the assembly of the first and second molds. 
   
   
     9. The method as claimed in  claim 3 , wherein the total curing step comprises an irradiation of the setting material from both sides of the assembly of the first and second molds. 
   
   
     10. The method as claimed in  claim 3 , wherein the total curing step comprises heating of the setting material. 
   
   
     11. The method as claimed in  claim 1  wherein the removing step comprises applying a thermal shock to the assembly of the first and second molds. 
   
   
     12. The method as claimed in  claim 1 , wherein the step of supplying a second mold comprises a step of trimming said second mold. 
   
   
     13. The method of  claim 1 , wherein the lens is an ophthalmic lens. 
   
   
     14. A method for molding a non-circular lens adapted to a wearer's prescription and to the shape of a frame chosen by the wearer, comprising the steps of:
 supplying a non-circular first mold substantially in the shape of the lens to be obtained; 
 supplying a second circular mold; 
 molding and curing a setting material between the first mold and a second mold, a maximum size of the first mold between two points of its perimeter being less than a diameter of the second mold and the first mold being positioned over the second mold; 
 removing the cured material lens from the first and second molds to define the lens; and 
 securing the lens to the frame, wherein the periphery of the cured material is not trimmed by more than a few millimeters prior to securing the lens to the frame. 
 
   
   
     15. The process as claimed in  claim 14 , wherein the step of molding comprises providing the second mold in a horizontal position. 
   
   
     16. The process as claimed in  claim 15 , wherein the step of molding comprises:
 positioning the second mold and 
 positioning the first mold. 
 
   
   
     17. The process as claimed in  claim 16 , wherein the step of molding comprises, after positioning the second mold, introducing the setting material in the second mold. 
   
   
     18. The process as claimed in  claim 16 , wherein the step of molding comprises, after positioning the first mold, injecting the setting material between the molds. 
   
   
     19. The process as claimed in  claim 16 , wherein the step of molding comprises, after positioning the second mold, positioning a ring seal. 
   
   
     20. The process as claimed in  claim 14 , further comprising the step of providing a ring seal around the first mold. 
   
   
     21. The process as claimed in  claim 1 , wherein the second mold is positioned 1 mm or less away from a periphery of the first mold when molding and curing the setting material. 
   
   
     22. The process as claimed in  claim 14 , wherein the second mold is positioned 1 mm or less away from a periphery of the first mold when molding and curing the setting material.